Wireless Power Transmission Antenna with Internal Repeater and In-Coil Tuning

ABSTRACT

An antenna for wireless power transmission includes a source coil comprised of a first conductive wire, the source coil including a first outer turn and a first inner turn, the source coil configured to connect to one or more electronic components for wireless power transfer. The antenna further includes an internal repeater coil comprised of a second conductive wire, the internal repeater coil including a second outer turn and a second inner turn, the internal repeater coil configured to have a repeater current induced in the second outer turn and the second inner turn. The antenna further includes a repeater tuning system in electrical connection with a beginning of the second outer turn and an ending of the second inner turn, the repeater tuning system positioned inward of the second outer turn.

TECHNICAL FIELD

The present disclosure generally relates to systems and methods forwireless transfer of electrical power and/or electrical data signals,and, more particularly, to wireless power transfer systems configuredfor substantial field uniformity over a large charge area.

BACKGROUND

Wireless connection systems are used in a variety of applications forthe wireless transfer of electrical energy, electrical power,electromagnetic energy, electrical data signals, among other knownwirelessly transmittable signals. Such systems often use inductiveand/or resonant inductive wireless power transfer, which occurs whenmagnetic fields created by a transmitting element induce an electricfield and, hence, an electric current, in a receiving element. Thesetransmitting and receiving elements will often take the form of coiledwires and/or antennas.

Transmission of one or more of electrical energy, electrical power,electromagnetic energy and/or electronic data signals from one of suchcoiled antennas to another, generally, operates at an operatingfrequency and/or an operating frequency range. The operating frequencymay be selected for a variety of reasons, such as, but not limited to,power transfer characteristics, power level characteristics,self-resonant frequency restraints, design requirements, adherence tostandards bodies’ required characteristics (e.g. electromagneticinterference (EMI) requirements, specific absorption rate (SAR)requirements, among other things), bill of materials (BOM), and/or formfactor constraints, among other things. It is to be noted that,“self-resonating frequency,” as known to those having skill in the art,generally refers to the resonant frequency of a passive component (e.g.,an inductor) due to the parasitic characteristics of the component.

When such systems operate to wirelessly transfer power from atransmission system to a receiver system via coils and/or antennas, itis often desired to simultaneously or intermittently communicateelectronic data from one system to the other. To that end, a variety ofcommunications systems, methods, and/or apparatus have been utilized forcombined wireless power and wireless data transfer. In some examplesystems, wireless power transfer related communications (e.g.,validation procedures, electronic characteristics data communications,voltage data, current data, device type data, among other contemplateddata communications) are performed using other circuitry, such asoptional Bluetooth chipsets and/or antennas for data communications,among other known communications circuits and/or antennas.

Further, when wireless power and data transfer is desired over a largecharge or powering area, variations in strength of an emitted field, bya transmitter, may limit operations in said charge or power area.

SUMMARY

Thus, wireless power transmission systems, capable of substantiallyuniform or with enhanced uniformity over a large charge area, aredesired. Such systems may be particularly advantageous in chargingscenarios where the power receiver or device associated with the powerreceiver is regularly moving or in motion, during a charge cycle.

In some examples, the wireless power transmission systems may beconfigured to transmit power over a large charge area, within which awireless power receiver system may receive said power. A “charge area”may be an area associated with and proximate to a wireless powertransmission system and/or a transmission antenna and within said area awireless power receiver 3 is capable of coupling with the transmissionsystem or transmission antenna at a plurality of points within thecharge area. To that end, it is advantageous, both for functionality anduser experience, that the plurality of points for coupling within acharge area include as many points as possible and with as much of aconsistent ability to couple with a receiver system, within the givencharge area. It is advantageous for large area power transmitters to bedesigned with maximum uniformity of power transmission in mind. Thus, itmay be advantageous to design such transmission antennas with uniformityratio in mind. “Uniformity ratio,” as defined herein, refers to theratio of a maximum coupling, between a wireless transmission system andwireless receiver system, to a minimum coupling between said systems,wherein said coupling values are determined by measuring or determininga coupling between the systems at a plurality of points at which thewireless receiver system and/or antenna are placed within the chargearea of the transmission antenna.

Further, while uniformity ratio can be enhanced by using more turns,coils, and/or other resonant bodies within an antenna, increasing suchuse of more conductive metals to maximize uniformity ratio may give riseto cost concerns, bill of material concerns, environmental concerns,and/or sustainability concerns, among other known drawbacks frominclusion of more conductive materials. To that end, the followingtransmission antennas may be designed by balancing uniformity ratioconsiderations with cost, environmental, and/or sustainabilityconsiderations. In other words, the following transmission antennas maybe configured to achieve an increased (e.g., maximized) uniformityratio, while reducing (e.g., minimizing) the use or the length ofconductive wires and/or traces.

Large area power transmission systems may further be configured to havemaximal metal resiliency. “Metal resiliency,” as defined herein, refersto the ability of a transmission antenna and/or a wireless transmissionsystem, itself, to avoid degradation in wireless power transferperformance when a metal or metallic material is present in anenvironment wherein the wireless transmission system operates. Forexample, metal resiliency may refer to the ability of wirelesstransmission system to maintain its inductance for power transfer, whena metallic body is present proximate to the transmission antenna.Additionally or alternatively, eddy currents generated by a metal body’spresence proximate to the transmission system may degrade performance inwireless power transfer and, thus, induction of such currents are to beavoided.

Large charge area antennas may utilize internal repeaters for expandingcharge area. An “internal repeater” as defined herein is a repeater coilor antenna that is utilized as part of a common antenna for a system,rather than as a repeater outside the bounds of such an antenna (e.g., aperipheral antenna for extending a signal outside the bounds of atransmission antenna’s charge area). For example, a user of the wirelesspower transmission system would not know the difference between a systemwith an internal repeater and one in which all coils are wired to thetransmitter electrical components, so long as both systems are housed inan opaque mechanical housing. Internal repeaters may be beneficial foruse in unitary wireless transmission antennas because they allow forlonger wires for coils, without introducing electromagnetic interference(EMI) that are associated with longer wires connected to a common wiredsignal source. Additionally or alternatively, use of internal repeatersmay be beneficial in improving metal resiliency and/or uniformity ratiofor the wireless transmission antenna(s) 21.

Some antennas with internal repeaters may be configured with alternatingcurrent directions of inner and outer turns. Thus, as one views theantenna both from left-to-right and from top-to-bottom, the currentdirection reverses from turn to turn. By reversing current directionsfrom turn-to-turn both laterally (side to side) and from top-to-bottom,optimal field uniformity may be maintained. By reversing currentdirections amongst inner and outer turns, both laterally andtop-to-bottom, a receiver antenna travelling across the charge area ofthe antenna will more often be positioned more closer-to-perpendicularwith the magnetic field emanating from the antenna. Thus, as a receiverantenna will best couple with the transmission antenna at points ofperpendicularity with the magnetic field, the charge area generated bythe antenna will have greater uniformity than if all of the turnscarried the current in a common direction.

By utilizing an internal repeater coil, rather than one larger sourcecoil, EMI benefits may be seen, as a shorter wire connected to thesource may reduce EMI issues. Additionally, by utilizing the internalrepeater coil, the aforementioned reversals of current direction may bebetter achieved, which enhances uniformity and metal resilience in thetransmission antenna.

In some examples, a repeater tuning system is disposed within or inclose proximity to the internal repeater coil, rather than by routinglong wires extending to a circuit board. By omitting such long wires,complexity of manufacture may be reduced. Additionally or alternatively,by shortening the connection to the tuning system by keeping it close bythe internal repeater coil, EMI concerns related to long connectingwires may be mitigated.

Sensitive demodulation circuits that allow for fast and accurate in-bandcommunications, regardless of the relative positions of the sender andreceiver within the power transfer range, are desired. The demodulationcircuit of the wireless power transmitters disclosed herein is a circuitthat is utilized to, at least in part, decode or demodulate ASK(amplitude shift keying) signals down to alerts for rising and fallingedges of a data signal. So long as the controller is programmed toproperly process the coding schema of the ASK modulation, thetransmission controller will expend less computational resources than itwould if it were required to decode the leading and falling edgesdirectly from an input current or voltage sense signal from the sensingsystem. To that end, the computational resources required by thetransmission controller to decode the wireless data signals aresignificantly decreased due to the inclusion of the demodulationcircuit.

This may in turn significantly reduce the BOM for the demodulationcircuit, and the wireless transmission system as a whole, by allowingusage of cheaper, less computationally capable processor(s) for or withthe transmission controller.

However, the throughput and accuracy of an edge-detection coding schemedepends in large part upon the system’s ability to quickly andaccurately detect signal slope changes. Moreover, in environmentswherein the distance between, and orientations of, the sender andreceiver may change dynamically, the magnitude of the received powersignal and embedded data signal may also change dynamically. Thiscircumstance may cause a previously readable signal to become too faintto discern, or may cause a previously readable signal to becomesaturated.

In accordance with yet another aspect of the disclosure, an antenna forwireless power transmission is disclosed. The antenna includes a sourcecoil comprised of a first conductive wire, the source coil including afirst outer turn and a first inner turn, the source coil configured toconnect to one or more electronic components for wireless powertransfer, the first conductive wire beginning at a first source terminalassociated with a beginning of the first outer turn and the conductivewire ending at a second source terminal associated with an ending of thefirst inner turn, the first conductive wire disposed such that a sourcecurrent flows in a first source direction through the first outer turnand a second source direction through the first inner turn, the secondsource direction substantially opposite of the first source direction.The antenna includes an internal repeater coil comprised of a secondconductive wire, the internal repeater coil including a second outerturn and a second inner turn, the internal repeater coil configured tohave a repeater current induced in the second outer turn and the secondinner turn, the second conductive wire disposed such that the repeatercurrent flows in a first repeater direction through the second outerturn and a second repeater direction through the second inner turn, thesecond repeater direction substantially opposite of the first repeaterdirection. The antenna further includes a repeater tuning system inelectrical connection with a beginning of the second outer turn and anending of the second inner turn, the repeater tuning system positionedinward of the second outer turn.

In a refinement, the repeater tuning system includes at least onecapacitor for tuning the internal repeater coil.

In a further refinement, the at least one capacitor is disposed on asubstrate independent of the one or more electronic components, thesubstrate positioned inward of the second outer turn.

In another further refinement, the at least one capacitor is aninterdigitated capacitor.

In yet a further refinement, the interdigitated capacitor is disposed ona substrate independent of the one or more electronic components, thesubstrate positioned inward of the second outer turn.

In yet another further refinement, the source coil and the internalrepeater coil are configured to be housed within a common mechanicalhousing and the interdigitated capacitor is disposed on a dielectricsurface of the mechanical housing that resides within a perimeterdefined by the second outer turn.

In a further refinement, the at least one capacitor is positionedradially inward of the second outer turn and radially outward of thesecond inner turn.

In another further refinement, the at least one capacitor is positionedradially inward of the second inner turn.

In a refinement, the first source direction and the first repeaterdirection are one of clockwise or counter-clockwise.

In a refinement, the source coil and the internal repeater coil combineto form a unitary transmission antenna.

In accordance with yet another aspect of the disclosure a wireless powertransmission system is disclosed. The system includes one or moreelectrical components configured for generating signals for one or bothof wireless power transmission and wireless data transmission. Thesystem further includes a source coil comprised of a first conductivewire, the source coil including a first outer turn and a first innerturn, the source coil configured to connect to one or more electroniccomponents for wireless power transfer, the first conductive wirebeginning at a first source terminal associated with a beginning of thefirst outer turn and the conductive wire ending at a second sourceterminal associated with an ending of the first inner turn, the firstconductive wire disposed such that a source current flows in a firstsource direction through the first outer turn and a second sourcedirection through the first inner turn, the second source directionsubstantially opposite of the first source direction. The system furtherincludes an internal repeater coil comprised of a second conductivewire, the internal repeater coil including a second outer turn and asecond inner turn, the internal repeater coil configured to have arepeater current induced in the second outer turn and the second innerturn, the second conductive wire disposed such that the repeater currentflows in a first repeater direction through the second outer turn and asecond repeater direction through the second inner turn, the secondrepeater direction substantially opposite of the first repeaterdirection. The system further includes a repeater tuning system inelectrical connection with a beginning of the second outer turn and anending of the second inner turn, the repeater tuning system positionedinward of the second outer turn. The source coil is configured towirelessly transmit wireless power signals generated by the one or moreelectrical components to the internal repeater coil and a wirelessreceiver system and the internal repeater coil is configured to receivethe wireless power signals and transmit repeated wireless power signalsto the wireless receiver system, the repeated wireless power signalsbased on the received wireless power signals.

In a refinement, the repeater tuning system includes at least onecapacitor for tuning the internal repeater coil.

In a further refinement, the at least one capacitor is disposed on asubstrate independent of the one or more electronic components, thesubstrate positioned inward of the second outer turn.

In another further refinement, the at least one capacitor is aninterdigitated capacitor.

In yet a further refinement, the interdigitated capacitor is disposed ona substrate independent of the one or more electronic components, thesubstrate positioned inward of the second outer turn.

In yet another further refinement, the source coil and the internalrepeater coil are configured to be housed within a common mechanicalhousing and the interdigitated capacitor is disposed on a dielectricsurface of the mechanical housing that resides within a perimeterdefined by the second outer turn.

In a refinement, the at least one capacitor is positioned radiallyinward of the second outer turn and radially outward of the second innerturn.

In a refinement, the at least one capacitor is positioned radiallyinward of the second inner turn.

In accordance with yet another aspect of the disclosure, an antenna forwireless power transmission is disclosed. The antenna includes a sourcecoil comprised of a first conductive wire, the source coil including afirst plurality of outer turns and a first plurality of inner turns, thesource coil configured to connect to one or more electronic componentsfor wireless power transfer, the first conductive wire beginning at afirst source terminal associated with a beginning of the first pluralityof outer turns and the conductive wire ending at a second sourceterminal associated with an ending of the first plurality of innerturns, the first conductive wire disposed such that a source currentflows in a first source direction through the first plurality of outerturns and a second source direction through the first plurality of innerturns, the second source direction substantially opposite of the firstsource direction. The antenna includes an internal repeater coilcomprised of a second conductive wire, the internal repeater coilincluding a second plurality of outer turns and a second plurality ofinner turns, the internal repeater coil configured to have a repeatercurrent induced in the second plurality of outer turns and the secondplurality of inner turns, the second conductive wire disposed such thatthe repeater current flows in a first repeater direction through thesecond plurality of outer turns and a second repeater direction throughthe second plurality of inner turns, the second repeater directionsubstantially opposite of the first repeater direction. The antennaincludes a repeater tuning system in electrical connection with abeginning of the plurality of second outer turns and an ending of theplurality of second inner turns, the repeater tuning system positionedinward of the plurality of second outer turns.

In a refinement, the first plurality of outer turns includes two turnsand the second plurality of outer turns includes two turns and firstplurality of inner turns includes three turns and the second pluralityof inner turns includes three turns.

These and other aspects and features of the present disclosure will bebetter understood when read in conjunction with the accompanyingdrawings.

While the present disclosure is directed to a system that can eliminatecertain shortcomings noted in or apparent from this Background section,it should be appreciated that such a benefit is neither a limitation onthe scope of the disclosed principles nor of the attached claims, exceptto the extent expressly noted in the claims. Additionally, thediscussion of technology in this Background section is reflective of theinventors’ own observations, considerations, and thoughts, and is in noway intended to accurately catalog or comprehensively summarize the artcurrently in the public domain. As such, the inventors expresslydisclaim this section as admitted or assumed prior art. Moreover, theidentification herein of a desirable course of action reflects theinventors’ own observations and ideas, and should not be assumed toindicate an art-recognized desirability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an embodiment of a system for wirelesslytransferring one or more of electrical energy, electrical power signals,electrical power, electromagnetic energy, electronic data, andcombinations thereof, in accordance with the present disclosure.

FIG. 2 is a block diagram illustrating components of a wirelesstransmission system of FIG. 1 and a wireless receiver system of FIG. 1 ,in accordance with FIG. 1 and the present disclosure.

FIG. 3 is a block diagram illustrating components of a transmissioncontrol system of the wireless transmission system of FIG. 2 , inaccordance with FIG. 1 , FIG. 2 , and the present disclosure.

FIG. 4 is a block diagram illustrating components of a sensing system ofthe transmission control system of FIG. 3 , in accordance with FIGS. 1-3and the present disclosure.

FIG. 5 is a block diagram of an example low pass filter of the sensingsystem of FIG. 4 , in accordance with FIGS. 1-4 and the presentdisclosure.

FIG. 6 is a block diagram illustrating components of a demodulationcircuit for the wireless transmission system of FIG. 2 , in accordancewith FIGS. 1-5 and the present disclosure.

FIG. 7A is a first portion of a schematic circuit diagram for thedemodulation circuit of FIG. 6 in accordance with an embodiment of thepresent disclosure.

FIG. 7B is a second portion of the schematic circuit diagram for thedemodulation circuit of FIGS. 6 and 7A, in accordance with an embodimentof the present disclosure.

FIG. 8 is a timing diagram for voltages of an electrical signal, as ittravels through the demodulation circuit, in accordance with FIGS. 1-7and the present disclosure.

FIG. 9 is a block diagram illustrating components of a powerconditioning system of the wireless transmission system of FIG. 2 , inaccordance with FIGS. 1-2 , and the present disclosure.

FIG. 10 is a block diagram illustrating components of a receiver controlsystem and a receiver power conditioning system of the wireless receiversystem of FIG. 2 , in accordance with FIGS. 1-2 , and the presentdisclosure.

FIG. 11A is a top view of a wireless power transmission antenna having asource coil and an internal repeater coil, in accordance with FIGS. 1-9and the present disclosure.

FIG. 11B is a top view of another wireless power transmission antennahaving a source coil and an internal repeater coil, in accordance withFIGS. 1-9, 11 , and the present disclosure.

FIG. 11C is a top view of a wireless power transmission antenna having asource coil and an internal repeater coil, with tuning capacitorsinternal of the inner repeater coil, in accordance with FIGS. 1-9,11A-B, and the present disclosure.

FIG. 11D is a top view of another wireless power transmission antennahaving a source coil and an internal repeater coil, with tuningcapacitors internal of the inner repeater coil, in accordance with FIGS.1-9, 11A-C, and the present disclosure.

FIG. 11E is a top view of another wireless power transmission antennahaving a source coil and an internal repeater coil, each coil having aplurality of turns, in accordance with FIGS. 1-9, 11A-D, and the presentdisclosure.

FIG. 12 is a top view of a non-limiting, exemplary antenna, for use as areceiver antenna of the system of FIGS. 1-10 and/or any other systems,methods, or apparatus disclosed herein, in accordance with the presentdisclosure.

While the following detailed description will be given with respect tocertain illustrative embodiments, it should be understood that thedrawings are not necessarily to scale and the disclosed embodiments aresometimes illustrated diagrammatically and in partial views. Inaddition, in certain instances, details which are not necessary for anunderstanding of the disclosed subject matter or which render otherdetails too difficult to perceive may have been omitted. It shouldtherefore be understood that this disclosure is not limited to theparticular embodiments disclosed and illustrated herein, but rather to afair reading of the entire disclosure and claims, as well as anyequivalents thereto. Additional, different, or fewer components andmethods may be included in the systems and methods.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth byway of examples in order to provide a thorough understanding of therelevant teachings. However, it should be apparent to those skilled inthe art that the present teachings may be practiced without suchdetails. In other instances, well known methods, procedures, components,and/or circuitry have been described at a relatively high-level, withoutdetail, in order to avoid unnecessarily obscuring aspects of the presentteachings.

Referring now to the drawings and with specific reference to FIG. 1 , awireless power transfer system 10 is illustrated. The wireless powertransfer system 10 provides for the wireless transmission of electricalsignals, such as, but not limited to, electrical energy, electricalpower, electrical power signals, electromagnetic energy, andelectronically transmittable data (“electronic data”). As used herein,the term “electrical power signal” refers to an electrical signaltransmitted specifically to provide meaningful electrical energy forcharging and/or directly powering a load, whereas the term “electronicdata signal” refers to an electrical signal that is utilized to conveydata across a medium.

The wireless power transfer system 10 provides for the wirelesstransmission of electrical signals via near field magnetic coupling. Asshown in the embodiment of FIG. 1 , the wireless power transfer system10 includes one or more wireless transmission systems 20 and one or morewireless receiver systems 30. A wireless receiver system 30 isconfigured to receive electrical signals from, at least, a wirelesstransmission system 20.

As illustrated, the wireless transmission system(s) 20 and wirelessreceiver system(s) 30 may be configured to transmit electrical signalsacross, at least, a separation distance or gap 17. A separation distanceor gap, such as the gap 17, in the context of a wireless power transfersystem, such as the system 10, does not include a physical connection,such as a wired connection. There may be intermediary objects located ina separation distance or gap, such as, but not limited to, air, acounter top, a casing for an electronic device, a plastic filament, aninsulator, a mechanical wall, among other things; however, there is nophysical, electrical connection at such a separation distance or gap.

Thus, the combination of two or more wireless transmission systems 20and wireless receiver system 30 create an electrical connection withoutthe need for a physical connection. As used herein, the term “electricalconnection” refers to any facilitation of a transfer of an electricalcurrent, voltage, and/or power from a first location, device, component,and/or source to a second location, device, component, and/ordestination. An “electrical connection” may be a physical connection,such as, but not limited to, a wire, a trace, a via, among otherphysical electrical connections, connecting a first location, device,component, and/or source to a second location, device, component, and/ordestination. Additionally or alternatively, an “electrical connection”may be a wireless power and/or data transfer, such as, but not limitedto, magnetic, electromagnetic, resonant, and/or inductive field, amongother wireless power and/or data transfers, connecting a first location,device, component, and/or source to a second location, device,component, and/or destination.

Further, while FIGS. 1-2 may depict wireless power signals and wirelessdata signals transferring only from one antenna (e.g., a transmissionantenna 21) to another antenna (e.g., a receiver antenna 31 and/or atransmission antenna 21), it is certainly possible that a transmittingantenna 21 may transfer electrical signals and/or couple with one ormore other antennas and transfer, at least in part, components of theoutput signals or magnetic fields of the transmitting antenna 21. Suchtransmission may include secondary and/or stray coupling or signaltransfer to multiple antennas of the system 10.

In some cases, the gap 17 may also be referenced as a “Z-Distance,”because, if one considers antennas 21, 31 each to be disposedsubstantially along respective common X-Y planes, then the distanceseparating the antennas 21, 31 is the gap in a “Z” or “depth” direction.However, flexible and/or non-planar coils are certainly contemplated byembodiments of the present disclosure and, thus, it is contemplated thatthe gap 17 may not be uniform, across an envelope of connectiondistances between the antennas 21, 31. It is contemplated that varioustunings, configurations, and/or other parameters may alter the possiblemaximum distance of the gap 17, such that electrical transmission fromthe wireless transmission system 20 to the wireless receiver system 30remains possible. Moreover, in an embodiment, the characteristics of thegap 17 can change during use, such as by an increase or decrease indistance and/or a change in relative device orientations.

The wireless power transfer system 10 operates when the wirelesstransmission system 20 and the wireless receiver system 30 are coupled.As used herein, the terms “couples,” “coupled,” and “coupling” generallyrefer to magnetic field coupling, which occurs when a transmitter and/orany components thereof and a receiver and/or any components thereof arecoupled to each other through a magnetic field. Such coupling mayinclude coupling, represented by a coupling coefficient (k), that is atleast sufficient for an induced electrical power signal, from atransmitter, to be harnessed by a receiver. Coupling of the wirelesstransmission system 20 and the wireless receiver system 30, in thesystem 10, may be represented by a resonant coupling coefficient of thesystem 10 and, for the purposes of wireless power transfer, the couplingcoefficient for the system 10 may be in the range of about 0.01 and 0.9.

As illustrated, at least one wireless transmission system 20 isassociated with an input power source 12. The input power source 12 maybe operatively associated with a host device, which may be anyelectrically operated device, circuit board, electronic assembly,dedicated charging device, or any other contemplated electronic device.Example host devices, with which the wireless transmission system 20 maybe associated therewith, include, but are not limited to including, adevice that includes an integrated circuit, a portable computing device,storage medium for electronic devices, charging apparatus for one ormultiple electronic devices, dedicated electrical charging devices,among other contemplated electronic devices.

The input power source 12 may be or may include one or more electricalstorage devices, such as an electrochemical cell, a battery pack, and/ora capacitor, among other storage devices. Additionally or alternatively,the input power source 12 may be any electrical input source (e.g., anyalternating current (AC) or direct current (DC) delivery port) and mayinclude connection apparatus from said electrical input source to thewireless transmission system 20 (e.g., transformers, regulators,conductive conduits, traces, wires, or equipment, goods, computer,camera, mobile phone, and/or other electrical device connection portsand/or adaptors, such as but not limited to USB ports and/or adaptors,among other contemplated electrical components).

Electrical energy received by the wireless transmission system(s) 20 isthen used for at least two purposes: to provide electrical power tointernal components of the wireless transmission system 20 and toprovide electrical power to the transmission antenna 21. Thetransmission antenna 21 is configured to wirelessly transmit theelectrical signals conditioned and modified for wireless transmission bythe wireless transmission system 20 via near-field magnetic coupling(NFMC). Near-field magnetic coupling enables the transfer of signalswirelessly through magnetic induction between the transmission antenna21 and one or more of receiving antenna 31 of, or associated with, thewireless receiver system 30, another transmission antenna 21, orcombinations thereof. Near-field magnetic coupling may be and/or bereferred to as “inductive coupling,” which, as used herein, is awireless power transmission technique that utilizes an alternatingelectromagnetic field to transfer electrical energy between twoantennas. Such inductive coupling is the near field wirelesstransmission of magnetic energy between two magnetically coupled coilsthat are tuned to resonate at a similar frequency. Accordingly, suchnear-field magnetic coupling may enable efficient wireless powertransmission via resonant transmission of confined magnetic fields.Further, such near-field magnetic coupling may provide connection via“mutual inductance,” which, as defined herein is the production of anelectromotive force in a circuit by a change in current in a secondcircuit magnetically coupled to the first.

In one or more embodiments, the inductor coils of either thetransmission antenna 21 or the receiver antenna 31 are strategicallypositioned to facilitate reception and/or transmission of wirelesslytransferred electrical signals through near field magnetic induction.Antenna operating frequencies may comprise relatively high operatingfrequency ranges, examples of which may include, but are not limited to,6.78 MHz (e.g., in accordance with the Rezence and/or Airfuel interfacestandard and/or any other proprietary interface standard operating at afrequency of 6.78 MHz), 13.56 MHz (e.g., in accordance with the NFCstandard, defined by ISO/IEC standard 18092), 27 MHz, and/or anoperating frequency of another proprietary operating mode. The operatingfrequencies of the antennas 21, 31 may be operating frequenciesdesignated by the International Telecommunications Union (ITU) in theIndustrial, Scientific, and Medical (ISM) frequency bands, including notlimited to 6.78 MHz, 13.56 MHz, and 27 MHz, which are designated for usein wireless power transfer.

The transmitting antenna and the receiving antenna of the presentdisclosure may be configured to transmit and/or receive electrical powerhaving a magnitude that ranges from about 10 milliwatts (mW) to about500 watts (W). In one or more embodiments the inductor coil of thetransmitting antenna 21 is configured to resonate at a transmittingantenna resonant frequency or within a transmitting antenna resonantfrequency band. A “coil” of a wireless power antenna (e.g., thetransmission antenna 21, the receiver antenna 31), as defined herein, isany conductor, wire, or other current carrying material, configured toresonate for the purposes of wireless power transfer and optionalwireless data transfer.

As known to those skilled in the art, a “resonant frequency” or“resonant frequency band” refers a frequency or frequencies whereinamplitude response of the antenna is at a relative maximum, or,additionally or alternatively, the frequency or frequency band where thecapacitive reactance has a magnitude substantially similar to themagnitude of the inductive reactance. In one or more embodiments, thetransmitting antenna resonant frequency is at a high frequency, as knownto those in the art of wireless power transfer.

The wireless receiver system 30 may be associated with at least oneelectronic device 14, wherein the electronic device 14 may be any devicethat requires electrical power for any function and/or for power storage(e.g., via a battery and/or capacitor). Additionally, the electronicdevice 14 may be any device capable of receipt of electronicallytransmissible data. For example, the device may be, but is not limitedto being, a handheld computing device, a mobile device, a portableappliance, a computer peripheral, an integrated circuit, an identifiabletag, a kitchen utility device, an electronic tool, an electric vehicle,a game console, a robotic device, a wearable electronic device (e.g., anelectronic watch, electronically modified glasses, altered-reality (AR)glasses, virtual reality (VR) glasses, among other things), a portablescanning device, a portable identifying device, a sporting good, anembedded sensor, an Internet of Things (IoT) sensor, IoT enabledclothing, IoT enabled recreational equipment, industrial equipment,medical equipment, a medical device a tablet computing device, aportable control device, a remote controller for an electronic device, agaming controller, among other things.

For the purposes of illustrating the features and characteristics of thedisclosed embodiments of FIGS. 1-10 , arrow-ended lines are utilized toillustrate transferrable and/or communicative signals and variouspatterns are used to illustrate electrical signals that are intended forpower transmission and electrical signals that are intended for thetransmission of data and/or control instructions. Solid lines indicatesignal transmission of electrical energy over a physical and/or wirelesspower transfer, in the form of power signals that are, ultimately,utilized in wireless power transmission from the wireless transmissionsystem 20 to the wireless receiver system 30. Further, dotted lines areutilized to illustrate electronically transmittable data signals, whichultimately may be wirelessly transmitted from the wireless transmissionsystem 20 to the wireless receiver system 30.

While the systems and methods herein illustrate the transmission ofwirelessly transmitted energy, wireless power signals, wirelesslytransmitted power, wirelessly transmitted electromagnetic energy, and/orelectronically transmittable data, it is certainly contemplated that thesystems, methods, and apparatus disclosed herein may be utilized in thetransmission of only one signal, various combinations of two signals, ormore than two signals and, further, it is contemplated that the systems,method, and apparatus disclosed herein may be utilized for wirelesstransmission of other electrical signals in addition to or uniquely incombination with one or more of the above mentioned signals. In someexamples, the signal paths of solid or dotted lines may represent afunctional signal path, whereas, in practical application, the actualsignal is routed through additional components en route to its indicateddestination. For example, it may be indicated that a data signal routesfrom a communications apparatus to another communications apparatus;however, in practical application, the data signal may be routed throughan amplifier, then through a transmission antenna, to a receiverantenna, where, on the receiver end, the data signal is decoded by arespective communications device of the receiver.

Turning now to FIGS. 2-3 , the wireless power transfer system 10 isillustrated as a block diagram including example sub-systems of both thewireless transmission systems 20 and the wireless receiver systems 30.The wireless transmission systems 20 may include, at least, a powerconditioning system 40, a transmission control system 26, a demodulationcircuit 70, a transmission tuning system 24, and the transmissionantenna 21. A first portion of the electrical energy input from theinput power source 12 may be configured to electrically power componentsof the wireless transmission system 20 such as, but not limited to, thetransmission control system 26.

A second portion of the electrical energy input from the input powersource 12 is conditioned and/or modified for wireless powertransmission, to the wireless receiver system 30, via the transmissionantenna 21. Accordingly, the second portion of the input energy ismodified and/or conditioned by the power conditioning system 40. Whilenot illustrated, it is certainly contemplated that one or both of thefirst and second portions of the input electrical energy may bemodified, conditioned, altered, and/or otherwise changed prior toreceipt by the power conditioning system 40 and/or transmission controlsystem 26, by further contemplated subsystems (e.g., a voltageregulator, a current regulator, switching systems, fault systems, safetyregulators, among other things).

Referring more specifically now to FIG. 3 , with continued reference toFIGS. 1 and 2 , subcomponents and/or systems of the transmission controlsystem 26 are illustrated. The transmission control system 26 mayinclude a sensing system 50, a transmission controller 28, a driver 48,a memory 27 and a demodulation circuit 70.

The transmission controller 28 may be any electronic controller orcomputing system that includes, at least, a processor which performsoperations, executes control algorithms, stores data, retrieves data,gathers data, controls and/or provides communication with othercomponents and/or subsystems associated with the wireless transmissionsystem 20, and/or performs any other computing or controlling taskdesired. The transmission controller 28 may be a single controller ormay include more than one controller disposed to control variousfunctions and/or features of the wireless transmission system 20.Functionality of the transmission controller 28 may be implemented inhardware and/or software and may rely on one or more data maps relatingto the operation of the wireless transmission system 20. To that end,the transmission controller 28 may be operatively associated with thememory 27.

The memory may include one or more of internal memory, external memory,and/or remote memory (e.g., a database and/or server operativelyconnected to the transmission controller 28 via a network, such as, butnot limited to, the Internet). The internal memory and/or externalmemory may include, but are not limited to including, one or more of aread only memory (ROM), including programmable read-only memory (PROM),erasable programmable read-only memory (EPROM or sometimes but rarelylabelled EROM), electrically erasable programmable read-only memory(EEPROM), random access memory (RAM), including dynamic RAM (DRAM),static RAM (SRAM), synchronous dynamic RAM (SDRAM), single data ratesynchronous dynamic RAM (SDR SDRAM), double data rate synchronousdynamic RAM (DDR SDRAM, DDR2, DDR3, DDR4), and graphics double data ratesynchronous dynamic RAM (GDDR SDRAM, GDDR2, GDDR3, GDDR4, GDDR5, a flashmemory, a portable memory, and the like. Such memory media are examplesof nontransitory machine readable and/or computer readable memory media.

While particular elements of the transmission control system 26 areillustrated as independent components and/or circuits (e.g., the driver48, the memory 27, the sensing system 50, among other contemplatedelements) of the transmission control system 26, such components may beintegrated with the transmission controller 28. In some examples, thetransmission controller 28 may be an integrated circuit configured toinclude functional elements of one or both of the transmissioncontroller 28 and the wireless transmission system 20, generally.

As illustrated, the transmission controller 28 is in operativeassociation, for the purposes of data transmission, receipt, and/orcommunication, with, at least, the memory 27, the power conditioningsystem 40, the driver 48, and the sensing system 50. The driver 48 maybe implemented to control, at least in part, the operation of the powerconditioning system 40. In some examples, the driver 48 may receiveinstructions from the transmission controller 28 to generate and/oroutput a generated pulse width modulation (PWM) signal to the powerconditioning system 40. In some such examples, the PWM signal may beconfigured to drive the power conditioning system 40 to outputelectrical power as an alternating current signal, having an operatingfrequency defined by the PWM signal. In some examples, PWM signal may beconfigured to generate a duty cycle for the AC power signal output bythe power conditioning system 40. In some such examples, the duty cyclemay be configured to be about 50% of a given period of the AC powersignal.

The sensing system may include one or more sensors, wherein each sensormay be operatively associated with one or more components of thewireless transmission system 20 and configured to provide informationand/or data. The term “sensor” is used in its broadest interpretation todefine one or more components operatively associated with the wirelesstransmission system 20 that operate to sense functions, conditions,electrical characteristics, operations, and/or operating characteristicsof one or more of the wireless transmission system 20, the wirelessreceiving system 30, the input power source 12, the host device 11, thetransmission antenna 21, the receiver antenna 31, along with any othercomponents and/or subcomponents thereof.

As illustrated in the embodiment of FIG. 4 , the sensing system 50 mayinclude, but is not limited to including, a thermal sensing system 52,an object sensing system 54, a receiver sensing system 56, a currentsensor 57, and/or any other sensor(s) 58. Within these systems, theremay exist even more specific optional additional or alternative sensingsystems addressing particular sensing aspects required by anapplication, such as, but not limited to: a condition-based maintenancesensing system, a performance optimization sensing system, astate-of-charge sensing system, a temperature management sensing system,a component heating sensing system, an IoT sensing system, an energyand/or power management sensing system, an impact detection sensingsystem, an electrical status sensing system, a speed detection sensingsystem, a device health sensing system, among others. The object sensingsystem 54, may be a foreign object detection (FOD) system.

Each of the thermal sensing system 52, the object sensing system 54, thereceiver sensing system 56, the current sensor 57 and/or the othersensor(s) 58, including the optional additional or alternative systems,are operatively and/or communicatively connected to the transmissioncontroller 28. The thermal sensing system 52 is configured to monitorambient and/or component temperatures within the wireless transmissionsystem 20 or other elements nearby the wireless transmission system 20.The thermal sensing system 52 may be configured to detect a temperaturewithin the wireless transmission system 20 and, if the detectedtemperature exceeds a threshold temperature, the transmission controller28 prevents the wireless transmission system 20 from operating. Such athreshold temperature may be configured for safety considerations,operational considerations, efficiency considerations, and/or anycombinations thereof. In a non-limiting example, if, via input from thethermal sensing system 52, the transmission controller 28 determinesthat the temperature within the wireless transmission system 20 hasincreased from an acceptable operating temperature to an undesiredoperating temperature (e.g., in a non-limiting example, the internaltemperature increasing from about 20° C. (C) to about 50° C., thetransmission controller 28 prevents the operation of the wirelesstransmission system 20 and/or reduces levels of power output from thewireless transmission system 20. In some non-limiting examples, thethermal sensing system 52 may include one or more of a thermocouple, athermistor, a negative temperature coefficient (NTC) resistor, aresistance temperature detector (RTD), and/or any combinations thereof.

As depicted in FIG. 4 , the transmission sensing system 50 may includethe object sensing system 54. The object sensing system 54 may beconfigured to detect one or more of the wireless receiver system 30and/or the receiver antenna 31, thus indicating to the transmissioncontroller 28 that the receiver system 30 is proximate to the wirelesstransmission system 20. Additionally or alternatively, the objectsensing system 54 may be configured to detect presence of unwantedobjects in contact with or proximate to the wireless transmission system20. In some examples, the object sensing system 54 is configured todetect the presence of an undesired object. In some such examples, ifthe transmission controller 28, via information provided by the objectsensing system 54, detects the presence of an undesired object, then thetransmission controller 28 prevents or otherwise modifies operation ofthe wireless transmission system 20. In some examples, the objectsensing system 54 utilizes an impedance change detection scheme, inwhich the transmission controller 28 analyzes a change in electricalimpedance observed by the transmission antenna 20 against a known,acceptable electrical impedance value or range of electrical impedancevalues.

Additionally or alternatively, the object sensing system 54 may utilizea quality factor (Q) change detection scheme, in which the transmissioncontroller 28 analyzes a change from a known quality factor value orrange of quality factor values of the object being detected, such as thereceiver antenna 31. The “quality factor” or “Q” of an inductor can bedefined as (frequency (Hz)×inductance (H))/resistance (ohms), wherefrequency is the operational frequency of the circuit, inductance is theinductance output of the inductor and resistance is the combination ofthe radiative and reactive resistances that are internal to theinductor. “Quality factor,” as defined herein, is generally accepted asan index (figure of measure) that measures the efficiency of anapparatus like an antenna, a circuit, or a resonator. In some examples,the object sensing system 54 may include one or more of an opticalsensor, an electro-optical sensor, a Hall Effect sensor, a proximitysensor, and/or any combinations thereof. In some examples, the qualityfactor measurements, described above, may be performed when the wirelesspower transfer system 10 is performing in band communications.

The receiver sensing system 56 is any sensor, circuit, and/orcombinations thereof configured to detect a presence of any wirelessreceiving system that may be couplable with the wireless transmissionsystem 20. In some examples, the receiver sensing system 56 and theobject sensing system 54 may be combined, may share components, and/ormay be embodied by one or more common components. In some examples, ifthe presence of any such wireless receiving system is detected, wirelesstransmission of electrical energy, electrical power, electromagneticenergy, and/or data by the wireless transmission system 20 to saidwireless receiving system is enabled. In some examples, if the presenceof a wireless receiver system is not detected, continued wirelesstransmission of electrical energy, electrical power, electromagneticenergy, and/or data is prevented from occurring. Accordingly, thereceiver sensing system 56 may include one or more sensors and/or may beoperatively associated with one or more sensors that are configured toanalyze electrical characteristics within an environment of or proximateto the wireless transmission system 20 and, based on the electricalcharacteristics, determine presence of a wireless receiver system 30.

The current sensor 57 may be any sensor configured to determineelectrical information from an electrical signal, such as a voltage or acurrent, based on a current reading at the current sensor 57. Componentsof an example current sensor 57 are further illustrated in FIG. 5 ,which is a block diagram for the current sensor 57. The current sensor57 may include a transformer 51, a rectifier 53, and/or a low passfilter 55, to process the AC wireless signals, transferred via couplingbetween the wireless receiver system(s) 20 and wireless transmissionsystem(s) 30, to determine or provide information to derive a current(I_(Tx)) or voltage (V_(Tx)) at the transmission antenna 21. Thetransformer 51 may receive the AC wireless signals and either step up orstep down the voltage of the AC wireless signal, such that it canproperly be processed by the current sensor. The rectifier 53 mayreceive the transformed AC wireless signal and rectify the signal, suchthat any negative voltages remaining in the transformed AC wirelesssignal are either eliminated or converted to opposite positive voltages,to generate a rectified AC wireless signal. The low pass filter 55 isconfigured to receive the rectified AC wireless signal and filter out ACcomponents (e.g., the operating or carrier frequency of the AC wirelesssignal) of the rectified AC wireless signal, such that a DC voltage isoutput for the current (I_(Tx)) and/or voltage (V_(Tx)) at thetransmission antenna 21.

FIG. 6 is a block diagram for a demodulation circuit 70 for the wirelesstransmission system(s) 20, which is used by the wireless transmissionsystem 20 to simplify or decode components of wireless data signals ofan alternating current (AC) wireless signal, prior to transmission ofthe wireless data signal to the transmission controller 28. Thedemodulation circuit includes, at least, a slope detector 72 and acomparator 74. In some examples, the demodulation circuit 70 includes aset/reset (SR) latch 76.

In some examples, the demodulation circuit 70 may be an analog circuitcomprised of one or more passive components (e.g., resistors,capacitors, inductors, diodes, among other passive components) and/orone or more active components (e.g., operational amplifiers, logicgates, among other active components). Alternatively, it is contemplatedthat the demodulation circuit 70 and some or all of its components maybe implemented as an integrated circuit (IC). In either an analogcircuit or IC, it is contemplated that the demodulation circuit may beexternal of the transmission controller 28 and is configured to provideinformation associated with wireless data signals transmitted from thewireless receiver system 30 to the wireless transmission system 20.

The demodulation circuit 70 is configured to receive electricalinformation (e.g., I_(Tx), V_(Tx)) from at least one sensor (e.g., asensor of the sensing system 50), detect a change in such electricalinformation, determine if the change in the electrical information meetsor exceeds one of a rise threshold or a fall threshold. If the changeexceeds one of the rise threshold or the fall threshold, thedemodulation circuit 70 generates an output signal and also generatesand outputs one or more data alerts. Such data alerts are received bythe transmitter controller 28 and decoded by the transmitter controller28 to determine the wireless data signals.

In other words, in an embodiment, the demodulation circuit 70 isconfigured to monitor the slope of an electrical signal (e.g., slope ofa voltage signal at the power conditioning system 32 of a wirelessreceiver system 30) and to output an indication when said slope exceedsa maximum slope threshold or undershoots a minimum slope threshold. Suchslope monitoring and/or slope detection by the communications system 70is particularly useful when detecting or decoding an amplitude shiftkeying (ASK) signal that encodes the wireless data signals in-band ofthe wireless power signal (which is oscillating at the operatingfrequency).

In an ASK signal, as noted above, the wireless data signals are encodedby damping the voltage of the magnetic field between the wirelesstransmission system 20 and the wireless receiver system 30. Such dampingand subsequent re-rising of the voltage in the field is performed basedon an underlying encoding scheme for the wireless data signals (e.g.,binary coding, Manchester coding, pulse-width modulated coding, amongother known or novel coding systems and methods). The receiver of thewireless data signals (e.g., the wireless transmission system 20 in thisexample) can then detect rising and falling edges of the voltage of thefield and decode said rising and falling edges to demodulate thewireless data signals.

Ideally, an ASK signal would rise and fall instantaneously, with nodiscernable slope between the high voltage and the low voltage for ASKmodulation; however, in reality, there is a finite amount of time thatpasses when the ASK signal transitions from the “high” voltage to the“low” voltage and vice versa. Thus, the voltage or current signal to besensed by the demodulation circuit 70 will have some slope or rate ofchange in voltage when transitioning. By configuring the demodulationcircuit 70 to determine when said slope meets, overshoots and/orundershoots such rise and fall thresholds, established based on theknown maximum/minimum slope of the carrier signal at the operatingfrequency, the demodulation circuit can accurately detect rising andfalling edges of the ASK signal.

Thus, a relatively inexpensive and/or simplified circuit may be utilizedto at least partially decode ASK signals down to notifications or alertsfor rising and falling slope instances. As long as the transmissioncontroller 28 is programmed to understand the coding schema of the ASKmodulation, the transmission controller 28 will expend far lesscomputational resources than would have been needed to decode theleading and falling edges directly from an input current or voltagesense signal from the sensing system 50. To that end, as thecomputational resources required by the transmission controller 28 todecode the wireless data signals are significantly decreased due to theinclusion of the demodulation circuit 70, the demodulation circuit 70may significantly reduce BOM of the wireless transmission system 20, byallowing usage of cheaper, less computationally capable processor(s) foror with the transmission controller 28.

The demodulation circuit 70 may be particularly useful in reducing thecomputational burden for decoding data signals, at the transmittercontroller 28, when the ASK wireless data signals are encoded/decodedutilizing a pulse-width encoded ASK signals, in-band of the wirelesspower signals. A pulse-width encoded ASK signal is a signal wherein thedata is encoded as a percentage of a period of a signal. For example, atwo-bit pulse width encoded signal may encode a start bit as 20% of aperiod between high edges of the signal, encode “1” as 40% of a periodbetween high edges of the signal, and encode “0” as 60% of a periodbetween high edges of the signal, to generate a binary encoding formatin the pulse width encoding scheme.

Thus, as the pulse width encoding relies solely on monitoring rising andfalling edges of the ASK signal, the periods between rising times neednot be constant and the data signals may be asynchronous or “unclocked.”Examples of pulse width encoding and systems and methods to perform suchpulse width encoding are explained in greater detail in U.S. Pat. App.No. 16/735,342 titled “Systems and Methods for Wireless Power TransferIncluding Pulse Width Encoded Data Communications,” to Michael Katz,which is commonly owned by the owner of the instant application and ishereby incorporated by reference in its entirety, for all that itteaches without exclusion of any part thereof.

As noted above, slope detection, and hence in-band transfer of data, maybecome ineffective or inefficient when the signal strength varies fromthe parameters relied upon during design. For example, when the relativepositions of the data sender and data receiver vary significantly duringuse of the system, the electromagnetic coupling between sender andreceiver coils or antennas will also vary. Data detection and decodingare optimized for a particular coupling may fail or underperform atother couplings. As such, a high sensitivity non-saturating detectionsystem is needed to allow the system to operate in environments whereincoupling changes dynamically.

For example, referring to FIG. 7 , the signal created by the high passfilter 71 of the slope detector 72, prior to being amplified by OP_(SD),will vary as a result of varying coupling (as will the power signal,but, for the purposes of the discussion of in-band data, it has now beenfiltered out at this point). Thus, the difference in magnitude of theamplified signals will vary by even more. At the upper end,substantially improved coupling may cause saturation of OP_(SD), at saidupper end, if the system is tuned for small signal detection. Similarly,substantially degraded coupling may result in an undetectable signal ifthe system is tuned for high, good, and/or fair coupling. Moreover, apre-amp signal with a positive offset may result in clipped (e.g.,saturated) positive signals, post-amplification, unless gain is reduced;however, the reduced gain may in turn render negative signalsundetectable. Additionally, a varying load at the receiver may affectthe signal, necessitating the amplification of the data signal at theslope detector 72.

As such, instability in coupling is generally not well-tolerated byinductive charging systems, since it causes the filtered and amplifiedsignal to vary too greatly. For example, a phone placed into a fitteddock will stay in a specific location relative to the dock, and anycoupling therebetween will remain relatively constant. However, a phoneplaced on a desktop with an inductive charging station under the desktopmay not maintain a fixed relative location, nor a fixed relativeorientation and, thus, the range of coupling between the transmitter andthe receiver of the phone may vary during the charging process. Further,consider a wireless power system configured for directly powering and/orcharging a medical device, while the medical device resides within ahuman body. Due to natural displacement and/or internal movement oforganic elements of the human body, the medical device may not maintainconstant location, relative to the body and/or an associated chargerpositioned outside of the body, and, thus, the transmitter and receivermay couple at a wide range of high, good, fair, low, and/or insufficientcoupling levels. Further still, consider a computer peripheral beingcharged by a charging mat on a user’s desk. It may be desired to chargesaid peripheral, such as a mouse or other input device, during use ofthe device; such use of the peripheral will necessarily alter couplingduring use, as it will be moved regularly, with respect to positioningof the transmitting charging mat.

The effect caused by a difference in the coupling coefficient k can beillustrated by a few non-limiting examples. Consider a case wherein k =0.041, representing fairly strong coupling. In this case, the inducedvoltage delta (V_(delta)) may be about 160 mV, with the correspondingamplified signal running between a peak of 3.15 V and a nayaround a DCoffset of 1.86 V yabove and below the DC offset value).

Now consider a case in the same system wherein a coupling value of 0.01is exhibited, representing fairly weak coupling. This weakening couldhappen due to relative movement, intervening materials, or othercircumstance. Now V_(delta) may be about 15 mV, with the correspondingamplified signal running between a peak of 1.94 V and a nadir of 1.77 V,for a swing of about 140mV around a DC offset of 1.86 V (i.e., about 70mV above and below the DC offset value).

As can be seen from this example, while the strongly coupled case yieldsrobust signals, the weakly coupled case yields very small signals atop afairly large offset. While perhaps generally detectable, these signallevel present a significant risk of data errors and consequently loweredthroughput. Moreover, while there is room for increased amplification,the level of amplification, especially given the DC offset, isconstrained by the saturation level of the available economicaloperational amplifier circuits, which, in some examples may be about 4.0V.

However, in an embodiment, automatic gain control in amplification iscombined with a voltage offset in slope detection to allow the system toadapt to varying degrees of coupling. This is especially helpful insituations where the physical locations of the coupled devices are nottightly constrained during coupling.

Continuing with the example of FIG. 7 , in the illustrated circuit 72,the bias voltage V′_(Bias) for slope detection is provided by a voltagedivider 77 (including linked resistors R_(B1), R_(B2), R_(B3)), whichprovides a voltage between V_(in) and ground based on a control voltageV_(HB). Given the control voltage V_(HB), the bias voltage V′_(Bias) isset by adjusting a resistance in the voltage divider. In thisconnection, one of the resistors, e.g., R_(B3), may be a variableresistor, such as a digitally adjustable potentiometer, with thespecific resistance being generated via an adaptive bias and gainprotocol to be described below, e.g., R_(bias).

Similarly, in the illustrated circuit 72, the output voltage V_(SD)provided to the next stage, comparator 74, is first amplified at a levelset by a voltage divider 80 (including linked resistors R_(A1), R_(A2),R_(A3)), based on the control voltage V_(HA) to generate V′_(SD) (slopedetection signal). The amplification of V_(SD) to generate V′_(SD)(amplified slope detection signal) is similarly set via a variablepotentiometer in the voltage divider, e.g., R_(A1), being set to aspecific value, e.g., R_(gain) generated via an adaptive bias and gainprotocol to be described later below.

With respect to the aforementioned, non-limiting example, with automaticgain and bias in slope detection, the circuit is configured toaccommodate a V_(amp) _(slope) _(delta) of between 400 mv and 2.2 V, anda V_(amp DC) offset of between 1.8 V and 2.2 V. In order to determineappropriate offsets and gains, the system may employ a beaconingsequence state. The beaconing sequence ensures that the transmitter isgenerally able to detect the receiver at all possible allowed couplingpositions and orientations.

Referring still to FIG. 7 , the slope detector 72 includes a high passfilter 71 and an optional stabilizing circuit 73. The high pass filter71 is configured to monitor for higher frequency components of the ACwireless signals and may include, at least, a filter capacitor (C_(HF))and a filter resistor (R_(HF)). The values for C_(HF) and R_(HF) areselected and/or tuned for a desired cutoff frequency for the high passfilter 71. In some examples, the cutoff frequency for the high passfilter 71 may be selected as a value greater than or equal to about 1-2kHz, to ensure adequately fast slope detection by the slope detector 72,when the operating frequency of the system 10 is on the order of MHz(e.g., an operating frequency of about 6.78 MHz). In some examples, thehigh pass filter 71 is configured such that harmonic components of thedetected slope are unfiltered. In view of the current sensor 57 of FIG.5 , the high pass filter 71 and the low pass filter 55, in combination,may function as a bandpass filter for the demodulation circuit 70.

OP_(SD) is any operational amplifier having an adequate bandwidth forproper signal response, for outputting the slope of V_(Tx), but lowenough to attenuate components of the signal that are based on theoperating frequency and/or harmonics of the operating frequency.Additionally or alternatively, OP_(SD) may be selected to have a smallinput voltage range for V_(Tx), such that OP_(SD) may avoid unnecessaryerror or clipping during large changes in voltage at V_(Tx). Further, aninput bias voltage (V_(Bias)) for OP_(SD) may be selected based onvalues that ensure OP_(SD) will not saturate under boundary conditions(e.g., steepest slopes, largest changes in V_(Tx)). It is to be noted,and is illustrated in Plot B of FIG. 8 , that when no slope is detected,the output of the slope detector 72 will be V_(Bias).

As the passive components of the slope detector 72 will set theterminals and zeroes for a transfer function of the slope detector 72,such passive components must be selected to ensure stability. To thatend, if the desired and/or available components selected for C_(HF) andR_(HF) do not adequately set the terminals and zeros for the transferfunction, additional, optional stability capacitor(s) C_(ST) may beplaced in parallel with R_(HF) and stability resistor R_(ST) may beplaced in the input path to OP_(SD).

Output of the slope detector 72 (Plot B representing V_(SD)) mayapproximate the following equation:

$V_{SD}\mspace{6mu} = \mspace{6mu} - R_{HF}C_{HF}\frac{dV}{dt} + V_{Bias}$

Thus, V_(SD) will approximate to V_(Bias), when no change in voltage(slope) is detected, and Output V_(SD) of the slope detector 72 isrepresented in Plot B. As can be seen, the value of V_(SD) approximatesV_(Bias) when no change in voltage (slope) is detected, whereas V_(SD)will output the change in voltage (dV/dt), as scaled by the high passfilter 71, when V_(Tx) rises and falls between the high voltage and thelow voltage of the ASK modulation. The output of the slope detector 72,as illustrated in Plot B, may be a pulse, showing slope of V_(Tx) riseand fall.

V_(SD) is output to the comparator circuit(s) 74, which is configured toreceive V_(SD), compare V_(SD) to a rising rate of change for thevoltage (V_(SUp)) and a falling rate of change for the voltage(V_(SLo)). If V_(SD) exceeds or meets V_(SUp), then the comparatorcircuit will determine that the change in V_(Tx) meets the risethreshold and indicates a rising edge in the ASK modulation. If V_(SD)goes below or meets V_(SLow), then the comparator circuit will determinethat the change in V_(Tx) meets the fall threshold and indicates afalling edge of the ASK modulation. It is to be noted that V_(SUp) andV_(SLo) may be selected to ensure a symmetrical triggering.

FIG. 8 is an exemplary timing diagram illustrating signal shape orwaveform at various stages or sub-circuits of the demodulation circuit70. The input signal to the demodulation circuit 70 is illustrated inFIG. 8 as Plot A, showing rising and falling edges from a “high” voltage(V_(High)) perturbation on the transmission antenna 21 to a “low”voltage (V_(Low)) perturbation on the transmission antenna 21. Thevoltage signal of Plot A may be derived from, for example, a current(I_(TX)) sensed at the transmission antenna 21 by one or more sensors ofthe sensing system 50. Such rises and falls from V_(High) to V_(Low) maybe caused by load modulation, performed at the wireless receiversystem(s) 30, to modulate the wireless power signals to include thewireless data signals via ASK modulation. As illustrated, the voltage ofPlot A does not cleanly rise and fall when the ASK modulation isperformed; rather, a slope or slopes, indicating rate(s) of change,occur during the transitions from V_(High) to V_(LOW) and vice versa.

As illustrated in FIG. 7 , the slope detector 72 includes a high passfilter 71, an operation amplifier (OpAmp) OP_(SD), and an optionalstabilizing circuit 73. The high pass filter 71 is configured to monitorfor higher frequency components of the AC wireless signals and mayinclude, at least, a filter capacitor (C_(HF)) and a filter resistor(R_(HF)). The values for C_(HF) and R_(HF) are selected and/or tuned fora desired cutoff frequency for the high pass filter 71. In someexamples, the cutoff frequency for the high pass filter 71 may beselected as a value greater than or equal to about 1-2 kHz, to ensureadequately fast slope detection by the slope detector 72, when theoperating frequency of the system 10 is on the order of MHz (e.g., anoperating frequency of about 6.78 MHz). In some examples, the high passfilter 71 is configured such that harmonic components of the detectedslope are unfiltered. In view of the current sensor 57 of FIG. 5 , thehigh pass filter 71 and the low pass filter 55, in combination, mayfunction as a bandpass filter for the demodulation circuit 70.

OP_(SD) is any operational amplifier having an adequate bandwidth forproper signal response, for outputting the slope of V_(Tx), but lowenough to attenuate components of the signal that are based on theoperating frequency and/or harmonics of the operating frequency.Additionally or alternatively, OP_(SD) may be selected to have a smallinput voltage range for V_(Tx), such that OP_(SD) may avoid unnecessaryerror or clipping during large changes in voltage at V_(Tx). Further, aninput bias voltage (V_(Bias)) for OP_(SD) may be selected based onvalues that ensure OP_(SD) will not saturate under boundary conditions(e.g., steepest slopes, largest changes in V_(Tx)). It is to be noted,and is illustrated in Plot B of FIG. 8 , that when no slope is detected,the output of the slope detector 72 will be V_(Bias).

As the passive components of the slope detector 72 will set theterminals and zeroes for a transfer function of the slope detector 72,such passive components must be selected to ensure stability. To thatend, if the desired and/or available components selected for C_(HF) andR_(HF) do not adequately set the terminals and zeros for the transferfunction, additional, optional stability capacitor(s) C_(ST) may beplaced in parallel with R_(HF) and stability resistor R_(ST) may beplaced in the input path to OP_(SD).

Output of the slope detector 72 (Plot B representing V_(SD)) mayapproximate the following equation:

$V_{SD}\mspace{6mu} = \mspace{6mu} - R_{HF}C_{HF}\frac{dV}{dt} + V_{Bias}$

Thus, V_(SD) will approximate to V_(Bias), when no change in voltage(slope) is detected, and output V_(SD) of the slope detector 72 isrepresented in Plot B. As can be seen, the value of V_(SD) approximatesV_(Bias) when no change in voltage (slope) is detected, whereas V_(SD)will output the change in voltage (dV/dt), as scaled by the high passfilter 71, when V_(Tx) rises and falls between the high voltage and thelow voltage of the ASK modulation. The output of the slope detector 72,as illustrated in Plot B, may be a pulse, showing slope of V_(Tx) riseand fall.

V_(SD) is output to the comparator circuit(s) 74, which is configured toreceive V_(SD), compare V_(SD) to a rising rate of change for thevoltage (V_(SUp)) and a falling rate of change for the voltage(V_(SLo)). If V_(SD) exceeds or meets V_(SUp), then the comparatorcircuit will determine that the change in V_(Tx) meets the risethreshold and indicates a rising edge in the ASK modulation. If V_(SD)goes below or meets V_(SLow), then the comparator circuit will determinethat the change in V_(Tx) meets the fall threshold and indicates afalling edge of the ASK modulation. It is to be noted that V_(SUp) andV_(SLo) may be selected to ensure a symmetrical triggering.

In some examples, such as the comparator circuit 74 illustrated in FIG.6 , the comparator circuit 74 may comprise a window comparator circuit.In such examples, the V_(SUp) and V_(SLo) may be set as a fraction ofthe power supply determined by resistor values of the comparator circuit74. In some such examples, resistor values in the comparator circuit maybe configured such that

$V_{Sup}\mspace{6mu} = \mspace{6mu} V_{in}\mspace{6mu}\left\lbrack \frac{R_{U2}}{R_{U1} + R_{U2}} \right\rbrack$

$V_{SLo}\mspace{6mu} = \mspace{6mu} V_{in}\mspace{6mu}\left\lbrack \frac{R_{L2}}{R_{L1} + R_{L2}} \right\rbrack$

where Vin is a power supply determined by the comparator circuit 74.When V_(SD) exceeds the set limits for V_(Sup) or V_(SLo), thecomparator circuit 74 triggers and pulls the output (V_(Cout)) low.

Further, while the output of the comparator circuit 74 could be outputto the transmission controller 28 and utilized to decode the wirelessdata signals by signaling the rising and falling edges of the ASKmodulation, in some examples, the SR latch 76 may be included to addnoise reduction and/or a filtering mechanism for the slope detector 72.The SR latch 76 may be configured to latch the signal (Plot C) in asteady state to be read by the transmitter controller 28, until a resetis performed. In some examples, the SR latch 76 may perform functions oflatching the comparator signal and serve as an inverter to create anactive high alert out signal. Accordingly, the SR latch 76 may be any SRlatch known in the art configured to sequentially excite when the systemdetects a slope or other modulation excitation. As illustrated, the SRlatch 76 may include NOR gates, wherein such NOR gates may be configuredto have an adequate propagation delay for the signal. For example, theSR latch 76 may include two NOR gates (NOR_(Up), NOR_(Lo)), each NORgate operatively associated with the upper voltage output 78 of thecomparator 74 and the lower voltage output 79 of the comparator 74.

In some examples, such as those illustrated in Plot C, a reset of the SRlatch 76 is triggered when the comparator circuit 74 outputs detectionof V_(SUp) (solid plot on Plot C) and a set of the SR latch 76 istriggered when the comparator circuit 74 outputs V_(SLo) (dashed plot onPlot C). Thus, the reset of the SR latch 76 indicates a falling edge ofthe ASK modulation and the set of the SR latch 76 indicates a risingedge of the ASK modulation. Accordingly, as illustrated in Plot D, therising and falling edges, indicated by the demodulation circuit 70, areinput to the transmission controller 28 as alerts, which are decoded todetermine the received wireless data signal transmitted, via the ASKmodulation, from the wireless receiver system(s) 30.

The incoming signal VTX exemplified in the plots of FIG. 8 does not leadto excess bias or saturation because the values of V_(BIAS) and V_(G)are at appropriate levels, but the coupling environment may change(e.g., from strong to weak coupling), such that the existing V_(BIAS)and V_(G) are no longer appropriate and would no longer allow accuratesignal detection. However, automatic gain and bias routines are appliedas described herein to continually evaluate the system behavior and setV_(BIAS) and V_(G) such that accurate signal detection is providedthroughout the range of allowable coupling strengths.

Referring now to FIG. 9 , and with continued reference to FIGS. 1-4 , ablock diagram illustrating an embodiment of the power conditioningsystem 40 is illustrated. At the power conditioning system 40,electrical power is received, generally, as a DC power source, via theinput power source 12 itself or an intervening power converter,converting an AC source to a DC source (not shown). A voltage regulator46 receives the electrical power from the input power source 12 and isconfigured to provide electrical power for transmission by the antenna21 and provide electrical power for powering components of the wirelesstransmission system 21. Accordingly, the voltage regulator 46 isconfigured to convert the received electrical power into at least twoelectrical power signals, each at a proper voltage for operation of therespective downstream components: a first electrical power signal toelectrically power any components of the wireless transmission system 20and a second portion conditioned and modified for wireless transmissionto the wireless receiver system 30. As illustrated in FIG. 3 , such afirst portion is transmitted to, at least, the sensing system 50, thetransmission controller 28, and the communications system 29; however,the first portion is not limited to transmission to just thesecomponents and can be transmitted to any electrical components of thewireless transmission system 20.

The second portion of the electrical power is provided to an amplifier42 of the power conditioning system 40, which is configured to conditionthe electrical power for wireless transmission by the antenna 21. Theamplifier may function as an inverter, which receives an input DC powersignal from the voltage regulator 46 and generates an AC as output,based, at least in part, on PWM input from the transmission controlsystem 26. The amplifier 42 may be or include, for example, a powerstage invertor, such as a single field effect transistor (FET), a dualfield effect transistor power stage invertor or a quadruple field effecttransistor power stage invertor. The use of the amplifier 42 within thepower conditioning system 40 and, in turn, the wireless transmissionsystem 20 enables wireless transmission of electrical signals havingmuch greater amplitudes than if transmitted without such an amplifier.For example, the addition of the amplifier 42 may enable the wirelesstransmission system 20 to transmit electrical energy as an electricalpower signal having electrical power from about 10 mW to about 500 W. Insome examples, the amplifier 42 may be or may include one or moreclass-E power amplifiers. Class-E power amplifiers are efficiently tunedswitching power amplifiers designed for use at high frequencies (e.g.,frequencies from about 1 MHz to about 1 GHz). Generally, a single-endedclass-E amplifier employs a single-terminal switching element and atuned reactive network between the switch and an output load (e.g., theantenna 21). Class E amplifiers may achieve high efficiency at highfrequencies by only operating the switching element at points of zerocurrent (e.g., on-to-off switching) or zero voltage (off to onswitching). Such switching characteristics may minimize power lost inthe switch, even when the switching time of the device is long comparedto the frequency of operation. However, the amplifier 42 is certainlynot limited to being a class-E power amplifier and may be or may includeone or more of a class D amplifier, a class EF amplifier, an H invertoramplifier, and/or a push-pull invertor, among other amplifiers thatcould be included as part of the amplifier 42.

Turning now to FIG. 10 and with continued reference to, at least, FIGS.1 and 2 , the wireless receiver system 30 is illustrated in furtherdetail. The wireless receiver system 30 is configured to receive, atleast, electrical energy, electrical power, electromagnetic energy,and/or electrically transmittable data via near field magnetic couplingfrom the wireless transmission system 20, via the transmission antenna21. As illustrated in FIG. 9 , the wireless receiver system 30 includes,at least, the receiver antenna 31, a receiver tuning and filteringsystem 34, a power conditioning system 32, a receiver control system 36,and a voltage isolation circuit 70. The receiver tuning and filteringsystem 34 may be configured to substantially match the electricalimpedance of the wireless transmission system 20. In some examples, thereceiver tuning and filtering system 34 may be configured to dynamicallyadjust and substantially match the electrical impedance of the receiverantenna 31 to a characteristic impedance of the power generator or theload at a driving frequency of the transmission antenna 20.

As illustrated, the power conditioning system 32 includes a rectifier 33and a voltage regulator 35. In some examples, the rectifier 33 is inelectrical connection with the receiver tuning and filtering system 34.The rectifier 33 is configured to modify the received electrical energyfrom an alternating current electrical energy signal to a direct currentelectrical energy signal. In some examples, the rectifier 33 iscomprised of at least one diode. Some non-limiting exampleconfigurations for the rectifier 33 include, but are not limited toincluding, a full wave rectifier, including a center tapped full waverectifier and a full wave rectifier with filter, a half wave rectifier,including a half wave rectifier with filter, a bridge rectifier,including a bridge rectifier with filter, a split supply rectifier, asingle phase rectifier, a three phase rectifier, a voltage doubler, asynchronous voltage rectifier, a controlled rectifier, an uncontrolledrectifier, and a half controlled rectifier. As electronic devices may besensitive to voltage, additional protection of the electronic device maybe provided by clipper circuits or devices. In this respect, therectifier 33 may further include a clipper circuit or a clipper device,which is a circuit or device that removes either the positive half (tophalf), the negative half (bottom half), or both the positive and thenegative halves of an input AC signal. In other words, a clipper is acircuit or device that limits the positive amplitude, the negativeamplitude, or both the positive and the negative amplitudes of the inputAC signal.

Some non-limiting examples of a voltage regulator 35 include, but arenot limited to, including a series linear voltage regulator, a buckconvertor, a low dropout (LDO) regulator, a shunt linear voltageregulator, a step up switching voltage regulator, a step down switchingvoltage regulator, an inverter voltage regulator, a Zener controlledtransistor series voltage regulator, a charge pump regulator, and anemitter follower voltage regulator. The voltage regulator 35 may furtherinclude a voltage multiplier, which is as an electronic circuit ordevice that delivers an output voltage having an amplitude (peak value)that is two, three, or more times greater than the amplitude (peakvalue) of the input voltage. The voltage regulator 35 is in electricalconnection with the rectifier 33 and configured to adjust the amplitudeof the electrical voltage of the wirelessly received electrical energysignal, after conversion to AC by the rectifier 33. In some examples,the voltage regulator 35 may an LDO linear voltage regulator; however,other voltage regulation circuits and/or systems are contemplated. Asillustrated, the direct current electrical energy signal output by thevoltage regulator 35 is received at the load 16 of the electronic device14. In some examples, a portion of the direct current electrical powersignal may be utilized to power the receiver control system 36 and anycomponents thereof; however, it is certainly possible that the receivercontrol system 36, and any components thereof, may be powered and/orreceive signals from the load 16 (e.g., when the load 16 is a batteryand/or other power source) and/or other components of the electronicdevice 14.

The receiver control system 36 may include, but is not limited toincluding, a receiver controller 38, a communications system 39 and amemory 37. The receiver controller 38 may be any electronic controlleror computing system that includes, at least, a processor which performsoperations, executes control algorithms, stores data, retrieves data,gathers data, controls and/or provides communication with othercomponents and/or subsystems associated with the wireless receiversystem 30. The receiver controller 38 may be a single controller or mayinclude more than one controller disposed to control various functionsand/or features of the wireless receiver system 30. Functionality of thereceiver controller 38 may be implemented in hardware and/or softwareand may rely on one or more data maps relating to the operation of thewireless receiver system 30. To that end, the receiver controller 38 maybe operatively associated with the memory 37. The memory may include oneor both of internal memory, external memory, and/or remote memory (e.g.,a database and/or server operatively connected to the receivercontroller 38 via a network, such as, but not limited to, the Internet).The internal memory and/or external memory may include, but are notlimited to including, one or more of a read only memory (ROM), includingprogrammable read-only memory (PROM), erasable programmable read-onlymemory (EPROM or sometimes but rarely labelled EROM), electricallyerasable programmable read-only memory (EEPROM), random access memory(RAM), including dynamic RAM (DRAM), static RAM (SRAM), synchronousdynamic RAM (SDRAM), single data rate synchronous dynamic RAM (SDRSDRAM), double data rate synchronous dynamic RAM (DDR SDRAM, DDR2, DDR3,DDR4), and graphics double data rate synchronous dynamic RAM (GDDRSDRAM, GDDR2, GDDR3, GDDR4, GDDR5), a flash memory, a portable memory,and the like. Such memory media are examples of nontransitory computerreadable memory media.

Further, while particular elements of the receiver control system 36 areillustrated as subcomponents and/or circuits (e.g., the memory 37, thecommunications system 39, among other contemplated elements) of thereceiver control system 36, such components may be external of thereceiver controller 38. In some examples, the receiver controller 38 maybe and/or include one or more integrated circuits configured to includefunctional elements of one or both of the receiver controller 38 and thewireless receiver system 30, generally. As used herein, the term“integrated circuits” generally refers to a circuit in which all or someof the circuit elements are inseparably associated and electricallyinterconnected so that it is considered to be indivisible for thepurposes of construction and commerce. Such integrated circuits mayinclude, but are not limited to including, thin-film transistors,thick-film technologies, and/or hybrid integrated circuits.

In some examples, the wireless power transmission system 20 may beconfigured to transmit power over a large charge area, within which thewireless power receiver system 30 may receive said power. A “chargearea” may be an area associated with and proximate to a wireless powertransmission system 20 and/or a transmission antenna 21 and within saidarea a wireless power receiver 30 is capable of coupling with thetransmission system 20 or transmission antenna 21 at a plurality ofpoints within the charge area. To that end, it is advantageous, both forfunctionality and user experience, that the plurality of points forcoupling within a charge area include as many points as possible andwith as much of a consistent ability to couple with a receiver system30, within the given charge area. In some examples, a “large chargearea” may be a charge area wherein the X-Y axis spatial freedom iswithin an area bounded by a width (across the area, or in an “X” axisdirection) of about 150 mm to about 500 mm and bounded by a length(height of the area, or in an “Y” axis direction) of about 50 mm toabout 350 mm. While the following antennas 21 disclosed are applicableto “large area” or “large charge area” wireless power transmissionantennas, the teachings disclosed herein may also be applicable totransmission or receiver antennas having smaller or larger charge areas,then those discussed above.

It is advantageous for large area power transmitters to be designed withmaximum uniformity of power transmission in mind. Thus, it may beadvantageous to design such transmission antennas 21 with uniformityratio in mind. “Uniformity ratio,” as defined herein, refers to theratio of a maximum coupling, between a wireless transmission system 20and wireless receiver system 30, to a minimum coupling between saidsystems 20, 30, wherein said coupling values are determined by measuringor determining a coupling between the systems 20, 30 at a plurality ofpoints at which the wireless receiver system 30 and/or antenna 31 areplaced within the charge area of the transmission antenna 21. In otherwords, the uniformity ratio is a ratio between the coupling when thereceiver antenna 31 is positioned at a point, relative to thetransmission antenna 21 area, that provides the highest coupling(C_(MAX)) versus the coupling when the receiver antenna 31 is positionedat a point, relative to the charge area of the transmission antenna 21,that provides for the lowest coupling (C_(MIN)). Thus, uniformity ratiofor a charge area (U_(AREA)) may be defined as:

U_(AREA) = C_(MAX) / C_(MIN.)

To that end, a perfectly uniform charge area would have a uniformityratio of 1, as C_(MAX) = C_(MIN) for a fully uniform charge area.

Further, while uniformity ratio can be enhanced by using more turns,coils, and/or other resonant bodies within an antenna, increasing suchuse of more conductive metals to maximize uniformity ratio may give riseto cost concerns, bill of material concerns, environmental concerns,and/or sustainability concerns, among other known drawbacks frominclusion of more conductive materials. To that end, the followingtransmission antennas 21 may be designed by balancing uniformity ratioconsiderations with cost, environmental, and/or sustainabilityconsiderations. In other words, the following transmission antennas 21may be configured to achieve an increased (e.g., maximized) uniformityratio, while reducing (e.g., minimizing) the use or the length ofconductive wires and/or traces.

Further, while the following antennas 21 may be embodied by PCB or flexPCB antennas, in some examples, the following antennas 21 may be wirewound antennas that eschew the use of any standard PCB substrate. Byreducing or perhaps even eliminating the use of PCB substrate, cost andor environmental concerns associated with PCB substrates may be reducedand/or eliminated.

Turning now to FIG. 11A, another example of a wireless powertransmission antenna 921A, for transmitting wireless power to a receiversystem 30 over a large charge area, is illustrated. The antenna 921A maybe utilized as the transmission antenna 21 in any of the aforementionedwireless transmission systems 20. The transmission antenna(s) 925include multiple transmission coils 925, wherein at least onetransmission coil is a source coil 925A and at least one transmissioncoil 925 is an internal repeater coil 925B. The source coil 925A iscomprised of a first continuous conductive wire 924A and includes afirst outer turn 953A and a first inner turn 951A. While illustratedwith only one first outer turn 953A and one first inner turn 951A, it iscertainly contemplated that the antenna 921A may include multiple outerturns 953A and inner turns 951A. The source coil 925A is configured toconnect to one or more electronic components 120 of the wirelesstransmission system 20. The first conductive wire begins at a firstsource terminal 926, which leads to or is part of the beginning of thefirst outer turn 951A, and ends at a second source terminal, which isassociated or is part of the ending 928 of the first inner turn 951A.

The internal repeater coil 925B may take a similar shape to that of thesource coil 925A, but is not directly, electrically connected to the oneor more electrical components 120 of the wireless transmission system20. Rather, the internal repeater coil 925B is a repeater configured tohave a repeater current induced in it by the source coil 925A.

As defined herein, a “repeater” is an antenna or coil that is configuredto relay magnetic fields emanating between a transmission antenna (e.g.,the source coil 925A) and one or both of a receiver antenna 31 and oneor more other antennas or coils, when such subsequent coils or antennasare configured as repeaters. Thus, the internal repeater coil 925B maybe configured to relay electrical energy and/or data via NMFC from theinitial transmitting antenna (e.g., the source coil 925A) to a receiverantenna 31 or to another repeating antenna or coil. In one or moreembodiments, such repeating coils or antennas (e.g., the repeater coil925B) comprise an inductor coil capable of resonating at a frequencythat is about the same as the resonating frequency of the initialtransmitting antenna (e.g. the source coil 925A) and the receiverantenna 31. Further, it is certainly possible that an initialtransmitting antenna may transfer electrical signals and/or couple withone or more other antennas (repeaters or receivers) and transfer, atleast in part, components of the output signals or magnetic fields ofthe transmitting antenna. Such transmission may include secondary and/orstray coupling or signal transfer to multiple antennas of the system(s)10, 20, 30.

As mentioned, the coil 925B is referred to as an “internal repeater” toeither the transmission antenna 921, 21 and/or the wireless transmissionsystem 20, as it is contained as part of a common system 20 or antenna921, 21. An “internal repeater” as defined herein is a repeater coil orantenna that is utilized as part of a unitary antenna, rather than as arepeater outside the bounds of the overall system. For example, a userof the wireless power transmission system 20 would not know thedifference between a system 20 with an internal repeater and one inwhich all coils are wired to the electrical components 120, so long asboth systems are housed in an opaque mechanical housing (e.g., amechanical housing 960). Internal repeaters may be beneficial for use inunitary wireless transmission antennas because they allow for longerwires for coils, without introducing electromagnetic interference (EMI)that are associated with longer wires connected to a common wired signalsource. Additionally or alternatively, use of internal repeaters may bebeneficial in improving metal resiliency and/or uniformity ratio for thewireless transmission antenna(s) 21.

Configuration of the inner turns 951 and outer turns 953, with respectto one another, of the coils 925 is designed for controlling a directionof current flow through each of the coils 925. Current flow direction isillustrated by the dotted lines in FIG. 11A. As illustrated, the currentmay enter the source coil 925A, from the one or more electricalcomponents 120, at the first source terminal at the beginning of thefirst outer turn 953A and then flow through the first outer turn in afirst source coil direction. Said source coil direction may be, forexample, a clockwise direction, as illustrated. Then, at the end of thefirst outer turn 953A, where the first outer turn 953A turns into thefirst inner turn 951A, the current will change directions to a secondsource direction, which is substantially opposite of the first sourcedirection. In some examples and as illustrated, the second sourcedirection may be a counter-clockwise direction, which is substantiallyopposite of the clockwise direction of the current flow through thefirst outer turn 953A.

The internal repeater coil 925B is configured such that a current isinduced in it by the source coil 925A and direction(s) of the currentinduced in the internal repeater coil 925B is/are illustrated by thedotted lines in FIG. 11A. The induced current of the internal repeatercoil 925B may have a first repeater direction, flowing through thesecond outer turn 953B of the internal repeater coil 925B. The firstrepeater direction may be, for example and as illustrated, acounter-clockwise direction. Then, at the end of the second outer turn953B, where the second outer turn 953B turns into the second inner turn951B, the current will change directions to a second repeater direction,which is substantially opposite of the first repeater direction, In someexamples and as illustrated, the second source direction may be aclockwise direction, which is substantially opposite of thecounter-clockwise direction of the current flow through the second outerturn 953B.

As illustrated and described, the first repeater direction(counter-clockwise) may be substantially opposite of the first sourcedirection (clockwise). Thus, as one views the antenna 921 both fromleft-to-right and from top-to-bottom, the current direction reversesfrom turn to turn. By reversing current directions from turn-to-turnboth laterally (side to side) and from top-to-bottom, optimal fielduniformity may be maintained. By reversing current directions amongstinner and outer turns 951, 953, both laterally and top-to-bottom, areceiver antenna 31 travelling across the charge area of the antenna 921will more often be positioned more closer-to-perpendicular with themagnetic field emanating from the antenna 921. Thus, as a receiverantenna 31 will best couple with the transmission antenna 921 at pointsof perpendicularity with the magnetic field, the charge area generatedby the antenna 921 will have greater uniformity than if all of the turns951, 953 carried the current in a common direction.

As illustrated, the source coil 925A and the internal repeater coil 925Bmay be configured to be housed in a common, unitary housing 960. Byutilizing the internal repeater coil 925B, rather than one larger sourcecoil, EMI benefits may be seen, as a shorter wire connected to thesource may reduce EMI issues. Additionally, by utilizing the internalrepeater coil 925B, the aforementioned reversals of current directionmay be better achieved, which enhances uniformity and metal resiliencein the transmission antenna 921.

In some examples, while the internal repeater coil 925B may be a“passive” inductor (e.g., not connected directly, by wired means, to apower source), it still may be connected to one or more components of arepeater tuning system 923A. The repeater tuning system 923A may includeone or more components, such as a tuning capacitor, configured to tunethe internal repeater coil 925B to operate at an operating frequencysimilar to that of the source coil 925A and/or any receiver antenna(s)31, to which the repeater coil 925B intends to transfer wireless power.The repeater tuning system 923A may be positioned, in a signal path ofthe internal repeater coil 925B, connecting the beginning of the secondouter turn 953B and the ending of the second inner turn 951B, asillustrated.

One or more of the source coil 925A, the internal repeater coil 925B,and combinations thereof may form or combine to form a substantiallyrectangular shape, as illustrated. In some examples, such substantiallyrectangular shape(s) of one or more of the source coil 925A, theinternal repeater coil 925B, and combinations thereof may additionallyhave rounded edges, as illustrated in FIG. 11A. In some such examples,shape of the coils 925A, 925B may both be oriented in a “column” typerectangular formation, wherein, when viewed in a top view perspective,the coils 925A,B are arranged from top to bottom in a singular row.Alternatively, as illustrated in FIG. 11B and including like and/orsimilar elements to those of FIG. 11A as indicated by like referencenumbers, the coils 925C, D of FIG. 11B may be arranged in a “row” typeformation, where the coils 925C, D are arranged next to one another in a“side-to-side” lateral fashion. Any of the subsequently discussedantennas 921 having a source-internal repeater configuration may haveeither a “row formation” or a “column formation.”

FIG. 11C is another example of a transmission antenna 921C that has asource-internal repeater configuration, similar to those of FIGS. 11A,11B and, thus, including like or similar elements to those of FIGS. 11A,11B, which share common reference numbers and descriptions herein. Theantenna 921C includes a repeater tuning system 923B, which isfunctionally equivalent to the repeater tuning system 923A of FIGS. 11A,11B, but is disposed within the bounds of the inner repeater coil 925B.For example, the repeater tuning system 923B may be disposed on asubstrate 962 that is independent of the one or more electricalcomponents 120 of the wireless transmission system 20. In such examples,the substrate 962 and/or the tuning system 923B absent a substrate maybe positioned radially inward of the second outer turn 953B, asillustrated in FIG. 11C. Alternatively, as illustrated in an antenna921D of FIG. 11D, which includes like or similar elements to those ofFIGS. 11A-C which share common reference numbers and descriptionsherein, the tuning system 923B may be similarly connected to the outerand inner turns 953B, 951B, but the tuning system 923B and/or theassociated substrate 962 may be positioned radially inward of the secondinner turn 951B.

In some examples wherein the repeater tuning system 923B is disposedradially inward of the second outer turn 953B, one or more capacitors ofthe repeater tuning system 923B may be interdigitated capacitors. Aninterdigitated capacitor is an element for producing capacitor-likecharacteristics by using microstrip lines, which can be disposed asconductive materials on a substrate or other surface. To that end,capacitors of the repeater tuning system 923B may be interdigitatedcapacitors disposed on the substrate 962. Additionally or alternatively,interdigitated capacitors of the repeater tuning system 923B may bedisposed on another surface, such as a dielectric surface of the housing960.

By disposing the repeater tuning system within or in close proximity tothe internal repeater coil 925B, long wires extending to a circuitboard, such as one associated with the one or more components 120, maybe omitted. By omitting such long wires, complexity of manufacture maybe reduced. Additionally or alternatively, by shortening the connectionto the tuning system 923B by keeping it close by the internal repeatercoil 925B, EMI concerns related to long connecting wires may bemitigated.

Turning now to FIG. 11E, another antenna 921E is illustrated, having asource coil 925E and repeater coil 925F configuration and, thus,including like or similar elements to those of FIGS. 11A-D, which sharecommon reference numbers and descriptions herein. The antenna 921Eincludes a first plurality of outer turns 953E, a first plurality ofinner turns 951E, a second plurality of outer turns 953F, and a secondplurality of inner turns 951F. The source coil 925E is connected to theone or more electrical components via a first source terminal proximateto a beginning of the first plurality of outer turns 953E and a secondsource terminal proximate to an ending of the first plurality of innerturns 951E. The internal repeater coil 925F may be connected to arepeater tuning system 923 via a first repeater terminal proximate to abeginning of the second plurality of outer turns 953F and a secondrepeater terminal proximate to an ending of the second plurality ofinner turns 951F. Inter-turn capacitors may 957 be connected in betweenthe first plurality of outer turns 953E and the first plurality of innerturns 951E and in between the second plurality of outer turns 953F andthe second plurality of inner turns 951F In some examples, the first andsecond plurality of outer turns 953E, 953F may include about 2 turns andthe first and second plurality of inner turns 951E, 951F may includeabout 3 turns.

FIG. 12 illustrates an example, non-limiting embodiment of the receiverantenna 31 that may be used with any of the systems, methods, and/orapparatus disclosed herein. In the illustrated embodiment, the antenna31, is a flat spiral coil configuration. Non-limiting examples can befound in U.S. Pat. Nos. 9,941,743, 9,960,628, 9,941,743 all to Peraltaet al.; 9,948,129, 10,063,100 to Singh et al.; 9,941590 to Luzinski;9,960,629 to Rajagopalan et al.; and U.S. Pat. App. Nos. 2017/0040107,2017/0040105, 2017/0040688 to Peralta et al.; all of which are assignedto the assignee of the present application and incorporated fully hereinby reference.

In addition, the antenna 31 may be constructed having amulti-layer-multi-turn (MLMT) construction in which at least oneinsulator is positioned between a plurality of conductors. Non-limitingexamples of antennas having an MLMT construction that may beincorporated within the wireless transmission system(s) 20 and/or thewireless receiver system(s) 30 may be found in U.S. Pat. Nos. 8,610,530,8,653,927, 8,680,960, 8,692,641, 8,692,642, 8,698,590, 8,698,591,8,707,546, 8,710,948, 8,803,649, 8,823,481, 8,823,482, 8,855,786,8,898,885, 9,208,942, 9,232,893, and 9,300,046 to Singh et al., all ofwhich are assigned to the assignee of the present application areincorporated fully herein. These are merely exemplary antenna examples;however, it is contemplated that the antennas 31 may be any antennacapable of the aforementioned higher power, high frequency wirelesspower transfer.

The automatic gain and bias control described herein may significantlyreduce the BOM for the demodulation circuit, and the wirelesstransmission system as a whole, by allowing usage of cheaper, lesscomputationally capable processor(s) for or with the transmissioncontroller. The throughput and accuracy of an edge-detection codingscheme depends in large part upon the system’s ability to quickly andaccurately detect signal slope changes. These constraints may be bettermet in environments wherein the distance between, and orientations of,the sender and receiver change dynamically, or the magnitude of thereceived power signal and embedded data signal may change dynamically,via the disclosed automatic gain and bias control. This may allowreading of faint signals via appropriate gain, for example, while alsoavoiding saturation with respect to larger signals.

The systems, methods, and apparatus disclosed herein are designed tooperate in an efficient, stable and reliable manner to satisfy a varietyof operating and environmental conditions. The systems, methods, and/orapparatus disclosed herein are designed to operate in a wide range ofthermal and mechanical stress environments so that data and/orelectrical energy is transmitted efficiently and with minimal loss. Inaddition, the system 10 may be designed with a small form factor using afabrication technology that allows for scalability, and at a cost thatis amenable to developers and adopters. In addition, the systems,methods, and apparatus disclosed herein may be designed to operate overa wide range of frequencies to meet the requirements of a wide range ofapplications.

While illustrated as individual blocks and/or components of the wirelesstransmission system 20, one or more of the components of the wirelesstransmission system 20 may combined and/or integrated with one anotheras an integrated circuit (IC), a system-on-a-chip (SoC), among othercontemplated integrated components. To that end, one or more of thetransmission control system 26, the power conditioning system 40, thesensing system 50, the transmitter coil 21, and/or any combinationsthereof may be combined as integrated components for one or more of thewireless transmission system 20, the wireless power transfer system 10,and components thereof. Further, any operations, components, and/orfunctions discussed with respect to the wireless transmission system 20and/or components thereof may be functionally embodied by hardware,software, and/or firmware of the wireless transmission system 20.

Similarly, while illustrated as individual blocks and/or components ofthe wireless receiver system 30, one or more of the components of thewireless receiver system 30 may combined and/or integrated with oneanother as an IC, a SoC, among other contemplated integrated components.To that end, one or more of the components of the wireless receiversystem 30 and/or any combinations thereof may be combined as integratedcomponents for one or more of the wireless receiver system 30, thewireless power transfer system 10, and components thereof. Further, anyoperations, components, and/or functions discussed with respect to thewireless receiver system 30 and/or components thereof may befunctionally embodied by hardware, software, and/or firmware of thewireless receiver system 30.

In an embodiment, a ferrite shield may be incorporated within theantenna structure to improve antenna performance. Selection of theferrite shield material may be dependent on the operating frequency asthe complex magnetic permeability (µ=µ′-j*µ”) is frequency dependent.The material may be a polymer, a sintered flexible ferrite sheet, arigid shield, or a hybrid shield, wherein the hybrid shield comprises arigid portion and a flexible portion. Additionally, the magnetic shieldmay be composed of varying material compositions. Examples of materialsmay include, but are not limited to, zinc comprising ferrite materialssuch as manganese-zinc, nickel-zinc, copper-zinc, magnesium-zinc, andcombinations thereof.

As used herein, the phrase “at least one of” preceding a series ofitems, with the term “and” or “or” to separate any of the items,modifies the list as a whole, rather than each member of the list (i.e.,each item). The phrase “at least one of” does not require selection ofat least one of each item listed; rather, the phrase allows a meaningthat includes at least one of any one of the items, and/or at least oneof any combination of the items, and/or at least one of each of theitems. By way of example, the phrases “at least one of A, B, and C” or“at least one of A, B, or C” each refer to only A, only B, or only C;any combination of A, B, and C; and/or at least one of each of A, B, andC.

The predicate words “configured to”, “operable to”, and “programmed to”do not imply any particular tangible or intangible modification of asubject, but, rather, are intended to be used interchangeably. In one ormore embodiments, a processor configured to monitor and control anoperation or a component may also mean the processor being programmed tomonitor and control the operation or the processor being operable tomonitor and control the operation. Likewise, a processor configured toexecute code can be construed as a processor programmed to execute codeor operable to execute code.

A phrase such as “an aspect” does not imply that such aspect isessential to the subject technology or that such aspect applies to allconfigurations of the subject technology. A disclosure relating to anaspect may apply to all configurations, or one or more configurations.An aspect may provide one or more examples of the disclosure. A phrasesuch as an “aspect” may refer to one or more aspects and vice versa. Aphrase such as an “embodiment” does not imply that such embodiment isessential to the subject technology or that such embodiment applies toall configurations of the subject technology. A disclosure relating toan embodiment may apply to all embodiments, or one or more embodiments.An embodiment may provide one or more examples of the disclosure. Aphrase such an “embodiment” may refer to one or more embodiments andvice versa. A phrase such as a “configuration” does not imply that suchconfiguration is essential to the subject technology or that suchconfiguration applies to all configurations of the subject technology. Adisclosure relating to a configuration may apply to all configurations,or one or more configurations. A configuration may provide one or moreexamples of the disclosure. A phrase such as a “configuration” may referto one or more configurations and vice versa.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” or as an “example” is not necessarily to be construed aspreferred or advantageous over other embodiments. Furthermore, to theextent that the term “include,” “have,” or the like is used in thedescription or the claims, such term is intended to be inclusive in amanner similar to the term “comprise” as “comprise” is interpreted whenemployed as a transitional word in a claim. Furthermore, to the extentthat the term “include,” “have,” or the like is used in the descriptionor the claims, such term is intended to be inclusive in a manner similarto the term “comprise” as “comprise” is interpreted when employed as atransitional word in a claim.

All structural and functional equivalents to the elements of the variousaspects described throughout this disclosure that are known or latercome to be known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe claims. Moreover, nothing disclosed herein is intended to bededicated to the public regardless of whether such disclosure isexplicitly recited in the claims. No claim element is to be construedunder the provisions of 35 U.S.C. § 112, sixth paragraph, unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.”

Reference to an element in the singular is not intended to mean “one andonly one” unless specifically so stated, but rather “one or more.”Unless specifically stated otherwise, the term “some” refers to one ormore. Pronouns in the masculine (e.g., his) include the feminine andneuter gender (e.g., her and its) and vice versa. Headings andsubheadings, if any, are used for convenience only and do not limit thesubject disclosure.

While this specification contains many specifics, these should not beconstrued as limitations on the scope of what may be claimed, but ratheras descriptions of particular implementations of the subject matter.Certain features that are described in this specification in the contextof separate embodiments can also be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment can also be implemented in multipleembodiments separately or in any suitable sub-combination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to a subcombination or variation of a sub combination.

What is claimed is:
 1. An antenna for wireless power transmissioncomprising: a source coil comprised of a first conductive wire, thesource coil including a first outer turn and a first inner turn, thesource coil configured to connect to one or more electronic componentsfor wireless power transfer, the first conductive wire beginning at afirst source terminal associated with a beginning of the first outerturn and the conductive wire ending at a second source terminalassociated with an ending of the first inner turn, the first conductivewire disposed such that a source current flows in a first sourcedirection through the first outer turn and a second source directionthrough the first inner turn, the second source direction substantiallyopposite of the first source direction; an internal repeater coilcomprised of a second conductive wire, the internal repeater coilincluding a second outer turn and a second inner turn, the internalrepeater coil configured to have a repeater current induced in thesecond outer turn and the second inner turn, the second conductive wiredisposed such that the repeater current flows in a first repeaterdirection through the second outer turn and a second repeater directionthrough the second inner turn, the second repeater directionsubstantially opposite of the first repeater direction; and a repeatertuning system in electrical connection with a beginning of the secondouter turn and an ending of the second inner turn, the repeater tuningsystem positioned inward of the second outer turn.
 2. The antenna ofclaim 1, wherein the repeater tuning system includes at least onecapacitor for tuning the internal repeater coil.
 3. The antenna of claim2, wherein the at least one capacitor is disposed on a substrateindependent of the one or more electronic components, the substratepositioned inward of the second outer turn.
 4. The antenna of claim 2,wherein the at least one capacitor is an interdigitated capacitor. 5.The antenna of claim 4, wherein the interdigitated capacitor is disposedon a substrate independent of the one or more electronic components, thesubstrate positioned inward of the second outer turn.
 6. The antenna ofclaim 4, wherein the source coil and the internal repeater coil areconfigured to be housed within a common mechanical housing, and whereinthe interdigitated capacitor is disposed on a dielectric surface of themechanical housing that resides within a perimeter defined by the secondouter turn.
 7. The antenna of claim 2, wherein the at least onecapacitor is positioned radially inward of the second outer turn andradially outward of the second inner turn.
 8. The antenna of claim 2,wherein the at least one capacitor is positioned radially inward of thesecond inner turn.
 9. The antenna of claim 1, wherein the first sourcedirection and the first repeater direction are one of clockwise orcounter-clockwise.
 10. The antenna of claim 1, wherein the source coiland the internal repeater coil combine to form a unitary transmissionantenna.
 11. A wireless power transmission system comprising: one ormore electrical components configured for generating signals for one orboth of wireless power transmission and wireless data transmission; asource coil comprised of a first conductive wire, the source coilincluding a first outer turn and a first inner turn, the source coilconfigured to connect to one or more electronic components for wirelesspower transfer, the first conductive wire beginning at a first sourceterminal associated with a beginning of the first outer turn and theconductive wire ending at a second source terminal associated with anending of the first inner turn, the first conductive wire disposed suchthat a source current flows in a first source direction through thefirst outer turn and a second source direction through the first innerturn, the second source direction substantially opposite of the firstsource direction; an internal repeater coil comprised of a secondconductive wire, the internal repeater coil including a second outerturn and a second inner turn, the internal repeater coil configured tohave a repeater current induced in the second outer turn and the secondinner turn, the second conductive wire disposed such that the repeatercurrent flows in a first repeater direction through the second outerturn and a second repeater direction through the second inner turn, thesecond repeater direction substantially opposite of the first repeaterdirection; a repeater tuning system in electrical connection with abeginning of the second outer turn and an ending of the second innerturn, the repeater tuning system positioned inward of the second outerturn, wherein the source coil is configured to wirelessly transmitwireless power signals generated by the one or more electricalcomponents to the internal repeater coil and a wireless receiver system,and wherein the internal repeater coil is configured to receive thewireless power signals and transmit repeated wireless power signals tothe wireless receiver system, the repeated wireless power signals basedon the received wireless power signals.
 12. The wireless powertransmission system of claim 11, wherein the repeater tuning systemincludes at least one capacitor for tuning the internal repeater coil.13. The wireless power transmission system of claim 12, wherein the atleast one capacitor is disposed on a substrate independent of the one ormore electronic components, the substrate positioned inward of thesecond outer turn.
 14. The wireless power transmission system of claim12, wherein the at least one capacitor is an interdigitated capacitor.15. The wireless power transmission system of claim 14, wherein theinterdigitated capacitor is disposed on a substrate independent of theone or more electronic components, the substrate positioned inward ofthe second outer turn.
 16. The wireless power transmission system ofclaim 14, wherein the source coil and the internal repeater coil areconfigured to be housed within a common mechanical housing, and whereinthe interdigitated capacitor is disposed on a dielectric surface of themechanical housing that resides within a perimeter defined by the secondouter turn.
 17. The wireless power transmission system of claim 12,wherein the at least one capacitor is positioned radially inward of thesecond outer turn and radially outward of the second inner turn.
 18. Thewireless power transmission system of claim 12, wherein the at least onecapacitor is positioned radially inward of the second inner turn.
 19. Anantenna for wireless power transmission comprising: a source coilcomprised of a first conductive wire, the source coil including a firstplurality of outer turns and a first plurality of inner turns, thesource coil configured to connect to one or more electronic componentsfor wireless power transfer, the first conductive wire beginning at afirst source terminal associated with a beginning of the first pluralityof outer turns and the conductive wire ending at a second sourceterminal associated with an ending of the first plurality of innerturns, the first conductive wire disposed such that a source currentflows in a first source direction through the first plurality of outerturns and a second source direction through the first plurality of innerturns, the second source direction substantially opposite of the firstsource direction; an internal repeater coil comprised of a secondconductive wire, the internal repeater coil including a second pluralityof outer turns and a second plurality of inner turns, the internalrepeater coil configured to have a repeater current induced in thesecond plurality of outer turns and the second plurality of inner turns,the second conductive wire disposed such that the repeater current flowsin a first repeater direction through the second plurality of outerturns and a second repeater direction through the second plurality ofinner turns, the second repeater direction substantially opposite of thefirst repeater direction; and a repeater tuning system in electricalconnection with a beginning of the plurality of second outer turns andan ending of the plurality of second inner turns, the repeater tuningsystem positioned inward of the plurality of second outer turns.
 20. Theantenna of claim 19, wherein the first plurality of outer turns includestwo turns and the second plurality of outer turns includes two turns,and wherein the first plurality of inner turns includes three turns andthe second plurality of inner turns includes three turns.